Hi Justine,
I would have to see the passage to be sure, and I do not have access to the AAMC passages.
However, I do know that I don't have the structure of hydroquinone memorized even as a chem graduate student, so I think you would not need to know this for the MCAT, or everyone would probably get that question wrong :).
If you give me more clarification on what the question entails, I can see how one might solve it.
Sorry for the inconvenience,
Katt